Conventional battery chargers, e.g., battery chargers used in laptop computers and cell phones, can result in 10-15% of dissipated power, e.g., for a 30 W system, 3-4.5 W can be dissipated in the battery charger, which may cause a significant thermal problem for system design, and may limit system performance. Currently the battery charger may also occupy a significant printed circuit board area, e.g., 300-400 mm2 for a 30 W system.
A battery charger, including its associated components, e.g., field effect transistors (FETs) and one or more inductors, may be designed to support a maximum power capability (e.g., capacity) of an AC/DC adapter shipped with the system (e.g., 30 W in this example). If a higher-power AC/DC adapter is used, (e.g., 100 W), the battery charger may not be able to take advantage of this higher-power capability.